In most electronic power conversion circuits, a so-called “power” circuit or stage is used and delivers a relatively high current (in the range from one ampere to a few amperes) to a load. This, for example, concerns power supply circuits, and circuits for controlling power elements from an electronic circuit, etc. The DC/DC power conversion circuits convert a DC reference signal into a DC power signal.
The operation of a DC/DC converter is based on the principle of a switching of a DC power supply voltage, associated with a low-pass filtering. In some applications, the conversion does not necessarily go along with a modification of the value of the voltage with respect to the voltage of the control circuit, but rather with the generation of a current higher than that which can be supplied by the control circuit.
In some applications, two MOS transistors, typically respectively with a P channel and N channel, are series-coupled between two terminals for delivering a DC voltage. These two transistors are called power transistors since they are sized to withstand a relatively high current as compared with the current that the transistors of the control circuit can withstand.